A tamerican museum Novitates PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, NY 10024 Number 3655, 26 pp., 17 figures, 4 tables June 25, 2009
New Material of North American Side-Necked Turtles (Pleurodira: Bothremydidae)
EUGENE S. GAFFNEY,1 G. E. HOOKS, III,2 AND VINCENT P. SCHNEIDER3
ABSTRACT
New cranial and postcranial material of the pleurodire family Bothremydidae, subtribe Bothremydina, from the Gulf Coastal Plain of North America, clarifies the distribution of the genera Bothremys and Chedighaii. New skull material from the Campanian Tar Heel Formation of North Carolina shows the presence of both Bothremys and Chedighaii, based on a maxilla and lower jaw. Additionally, a series of otic chambers and basicrania, while providing important information on morphology, are identified as subtribe Bothremydina, genus and species indeterminate, as the basicranium alone is insufficient to distinguish Bothremys and Chedighaii. An associated skull-shell specimen belonging to the pleurodire subtribe Bothremydina from the Campanian Mooreville Chalk of Alabama, FMNH PR 247, identified in Gaffney et al. (2006) as Chedighaii barberi, is reinterpreted as belonging to the genus Bothremys. A maxilla and jugal fragment found among the material belonging to FMNH PR 247 shows that this specimen has a skull with deep pits on its triturating surface, diagnostic of the genus Bothremys, and in contrast to the flat triturating surface of Chedighaii. Because FMNH PR 247 has an associated partial skull and shell, it was the basis for placing the species “Podocnemis” barberi Schmidt, 1940, the type of which is a shell, in Chedighaii Gaffney et al., 2006. A result of this identification is that the species “Podocnemis” barberi Schmidt, 1940, cannot be assigned to a genus, as the shell morphology of Chedighaii Gaffney et al., 2006, and Bothremys Leidy, 1865, cannot be distinguished at present. A review of the shell material in the sub tribe Bothremydina concludes that shells alone are inadequate to reliably distinguish alpha-level taxa in this group at present. It is likely that ALAB PV 2001.2, NCSM 23681, and YPM PU 12951, here referred to Chedighaii sp., belong to a new species of Chedighaii, distinct from Chedighaii hutchisoni, but the material is too incomplete at present to adequately diagnosis it.
1 Division of Paleontology, American Museum of Natural History, New York, NY, USA ([email protected]). 2 Department of Biological and Environmental Sciences, Longwood University, Farmville, VA, USA (hooksge@ longwood.edu). 3 North Carolina Museum of Natural Sciences, Research and Collections, Raleigh, NC, USA 27601 (vince.schneider@ ncmail.net).
Copyright © American Museum of Natural History 2009 ISSN 0003-0082 2 AMERICAN MUSEUM NOVITATES NO. 3655
Fig. 1. Map of North Carolina Localities. Phoebus Landing on the Cape Fear River and the Bladen County Landfill Annex. [F. Ippolito, del.].
INTRODUCTION Bothremys and has consequences for several other specimens. Gaffney et al. (2006) reviewed and described After the completion and submission of the pleurodires of the tribe Bothremydini of Gaffney et al. (2006) manuscript, the senior North America, consisting of the genera author continued additional acid preparation Bothremys Leidy, 1865, and Chedighaii of the many fragments associated with FMNH Gaffney et al., 2006. The purpose of the PR 247. This resulted in the identification of present paper is to describe material from an isolated skull fragment that altered the North Carolina (fig. 1) and Alabama that was identification of that specimen and had not described in Gaffney et al. (2006), and to ramifications on the identification of other discuss the consequences of new identifica¬ North American bothremydid specimens. A tions of some specimens of Bothremys and summary of these results was appended to Chedighaii. This paper describes new skull Gaffney et al. (2006) as a “Note Added in material from the Cretaceous of North Proof’ (Gaffney et al., 2006: 698). Changes Carolina that significantly adds to our knowl¬ were also made to figure captions and the map edge of North American bothremydids. We (Gaffney et al., 2006: fig. 18). describe the shell of a Chedighai skull-shell The present paper is essentially a correction association, whose skull only has already been and extension of Gaffney et al. (2006) and described (Gaffney et al., 2006), and review requires that the reader be familiar with and the shell morphology of North American have access to that paper. Figures, descrip¬ Bothremydina. The discovery of new skull tions, and references to all of the bothremydid material belonging to a well-known shell- taxa referred to in this paper can be found in partial skull specimen, FMNH PR 247, alters Gaffney et al. (2006). The taxonomy and the identification of it from Chedighai to morphological nomenclature also follow that 2009 GAFFNEY ET AL.: NEW MATERIAL (PLEURODIRA: BOTHREMYDIDAE) 3 reference. The taxa discussed here are all dor dorsal included in the data set of Gaffney et al. ex exoccipital (2006: appendix 3) and are shown in clado- fcti foramen chorda tympani inferius grams in Gaffney et al. (2006: figs. 288-314). QP foramen jugulare posterius The reader should also see this work for fn fossa nasalis fnt foramen nervi trigemini further discussion of pleurodire phylogeny for fossa orbitalis and morphology. For convenience, an abbre¬ fp foramen praepalatinum viated classification from Gaffney et al. (2006) fpcci foramen posterius canalis carotici showing the higher categories and the new interni status of barberi Schmidt, 1940, follows: fpct foramen posterius chorda tympani fpo fenestra postotica fr Summary Classification of North frontal fst foramen stapediotemporale American Bothremydini ica incisura columellae auris Infraorder Pleurodira Cope, 1864 ju jugal la lacrimal Family Bothremydidae Baur, 1891 lar labial ridge lat lateral Subfamily Bothremydinae Baur, 1891 lhv lateral head vein mx maxilla Tribe Bothremydini Gaffney et al., 2006 op opisthotic pa parietal Subtribe Bothremydina Gaffney et al., 2006 pal palatine Bothremys cooki Leidy, 1865 pas processus articularis pf prefrontal Chedighaii hutchisoni Gaffney et al., 2006 pr prootic pt pterygoid Sub tribe Bothremydina indeterminate to genus: qu quadrate sa stapedial artery “Podocnemis” barberi (Schmidt, 1940) se sulcus eustachii so supraoccipital ABBREVIATIONS sot septum orbitotemporale sq squamosal Institutional Abbreviations tb tuberculum basioccipitale ALAB Alabama Museum of Natural ts triturating surface History, University of Alabama, ven ventral Tuscaloosa, Alabama, USA XII foramen nervi hypoglossi ANSP Academy of Natural Sciences of Philadelphia, Pennsylvania, USA BOTHREMYDID CRANIAL MATERIAL FMNH Field Museum of Natural History, FROM THE TAR HEEL FORMATION OF Chicago, Illinois, USA NORTH CAROLINA KUVP University of Kansas, Lawrence, Kansas, USA In the collections of the North Carolina NCSM North Carolina Museum of Natural State Museum of Natural History are skull Sciences, Raleigh, North Carolina, USA elements of bothremydids from the YPM Yale Peabody Museum, New Haven, Campanian Tar Heel Formation of North Connecticut, USA Carolina. These specimens are from two localities in Bladen County (fig. 1), Phoebus Landing on the Cape Fear River at milepost Anatomical Abbreviations 68 (Stephenson, 1912) and the Bladen County am area articularis mandibularis ant anterior Landfill Annex. The vertebrate fossils at these ap antrum postoticum localities are from a lag deposit located at the bo basioccipital top of the Tar Heel Formation. The Tar Heel bs basisphenoid Formation consists of deltaic facies in this part cc canalis cavernosus of North Carolina (Sohl and Owens, 1991). 4 AMERICAN MUSEUM NOVITATES NO. 3655
TABLE 1 TABLE 2 Measurements of North Carolina otic chambers Comparison of systematically important Bothremydina specimens from North America B of Gaffney Otic chamber et al. (2006) height Identification Consists of
NCSM 18650 150 35 AMNH 2521 Bothremys cooki skull and jaws NCSM 14227 208 58 holotype NCSM 12766 182 51 AMNH 29444 Bothremys cooki otic chamber and NCSM 14103 184 50 basicranium NCSM 14102 - 50 FMNH P26055 “Podocnemis” shell NCSM 14226 - 49 barberi holotype
Bothremys cooki holotype 72.2 - FMNH PR 247 Bothremys sp. partial skull and Chedighaii hutchisoni 182.0 - shell holotype ALAB PV 2001.2 Chedighaii sp. partial skull and ALAB PV2001.2 131.0 - shell KUVP 14765 Chedighaii skull hutchisoni Recent pollen analysis (Self-Trail et al., 2004) holotype determined that the vertebrate fauna from the YPM PU 12951 Chedighaii sp endocast of skull Tar Heel Formation at Phoebus Landing is NCSM 23681 Chedighaii sp partial maxilla from the upper part of the early Campanian. and jugal The cranial material includes a series of otic NCSM 14499 Bothremys sp. lower jaw chambers, a partial lower jaw, and a maxilla- jugal fragment. All of these specimens are well preserved in that they are uncrushed and taken as close as possible to the plane of the nearly free of matrix, allowing examination of standard occipital views. These results, also the internal areas of the otic chambers. It is shown in table 1, are consistent with the B only the incomplete nature of the otic cham¬ measurements and at least give a range of bers that limit their taxonomic usefulness, relative size for these specimens. and they are identifiable only as subtribe Except for the variable development of the Bothremydina. The quadrate of one of these, ridge described in NCSM 14227 (see below) all NCSM 12766, was figured in Gaffney et al. of the otic chambers agree closely with each (2006: fig. 286D). The lower jaw is identifiable other. All are very close in morphology to as Bothremys sp. and the maxilla is identifiable North American Bothremydina already de¬ as Chedighaii sp. scribed in Gaffney et al., (2006), namely: The North Carolina otic chambers and Chedighaii hutchisoni, Bothremys sp. FMNH partial braincases are too incomplete to obtain PR 247 (incorrectly identified in Gaffney et al., directly any of the measurements used in 2006, as “Chedighai barberi”), and Bothremys Gaffney et al. (2006: appendix 5, fig. 315). cooki. After study of the North Carolina However, in table 1 we have made an effort to specimens, there seems to be no basis for compare the relative sizes of these specimens. identifying any of them with one or more of An approximation of measurement B in the these named taxa. While the anterior half of the above-cited paper, skull width at the level of the Bothremydina skull shows systematic variation area articularis mandibularis, can be made for allowing taxonomic distinction, the otic cham¬ some specimens by doubling the distance from ber and basicranium is conservative and, except the condylus occipitalis to the lateral margin of for size, does not provide enough characters for the quadrate as preserved. This is probably less generic identification. Furthermore, there are than the true B measurement of a complete skull fragments (see below) identifiable as both skull because some of the cheek thickness is Bothremys and Chedighaii. missing in all the North Carolina specimens. NCSM 18650, subtribe Bothremydina, ge¬ Another possible measurement is the vertical nus and species indeterminate; right otic thickness or height of the otic chamber at the chamber with occipital portion of skull position of the foramen stapediotemporale, (figs. 2, 3, 8). Bladen County Landfill Annex, 2009 GAFFNEY ET AL.: NEW MATERIAL (PLEURODIRA: BOTHREMYDIDAE) 5
TABLE 3 Revised status of North American Bothremydina specimens
Specimen number Gaffney, Tong, and Meylan (2006) this paper
AMNH 2521 Bothremys cooki Bothremys cooki Bothremys cooki holotype AMNH 29444 Bothremys cooki Bothremys cooki FMNH P26055 Chedighaii barberi Bothremydina indet Podocnemis barberi holotype FMNH PR 247 Chedighaii barberi Bothremys sp. ALAB PV 2001.2 Chedighaii sp. Chedighaii sp. KUVP 14765 Chedighaii hutchisoni Chedighaii hutchisoni Chedighaii hutchisoni holotype YPM PU 12951 Chedighaii sp. Chedighaii sp. FMNH P27370 Chedighaii barberi Bothremydina indet ANSP 15902 Chedighaii barberi Bothremydina indet FMNH P27369 Chedighaii barberi Bothremydina indet YPM 3608 Chedighaii barberi Bothremydina indet FMNH P27372 Chedighaii barberi Bothremydina indet FMNH P27331 Chedighaii barberi Bothremydina indet NCSM 23681 (not known in 2006) Chedighaii sp. NCSM 14499 (not known in 2006) Bothremys sp. NCSM 18650 Chedighaii barberi Bothremydina indet NCSM 14227 Chedighaii barberi Bothremydina indet NCSM 12766 Chedighaii barberi Bothremydina indet NCSM 14103 Chedighaii barberi Bothremydina indet NCSM 14102 Chedighaii barberi Bothremydina indet NCSM 14226 Chedighaii barberi Bothremydina indet
Bladen County, North Carolina, Tar Heel talis. The posterior halves of both pterygoids Formation, Late Cretaceous, Campanian. are preserved, the right is more complete. This specimen is the best pleurodire skull The morphology of NCSM 18650 is similar element from the North Carolina Cretaceous, to that described for Chedighaii hutchisoni but it is still too incomplete for a generic (Gaffney et al., 2006: 361), Bothremys sp., identification. However, it is very close in size FMNH PR 247 (= Chedighaii barberi of and morphology to the skulls of Chedighaii Gaffney et al., 2006: 373), Chedighaii sp (= hutchisoni and Bothremys sp. FMNH PR 247. Chedighaii barberi of Gaffney et al., 2006: 373) It is nearly twice the size of the skull of and Bothremys cooki (Gaffney et al., 2006: 312), Bothremys cooki (fig. 8). The specimen con¬ all of which should be seen for comparison with sists of the right quadrate with some of the the North Carolina material figured here. In cavum tympani and all the processus articu- agreement with these specimens, NCSM 18650 laris preserved but lacking all the cheek and has the foramen posterius canalis carotici dermal roof contacts and edges. There seems interni formed between the pterygoid and to be a fragment of squamosal in the posterior quadrate, an incisura columellae auris that is a broken area. The right and left prootics and canal, a foramen nervi trigemini and foramen exoccipitals are preserved, along with the stapediotemporalis closely placed, and an ante¬ basisphenoid. The right opisthotic is present riorly facing foramen stapediotemporalis. In the lacking its lateral edges; only the medial occipital view of NCSM 18650, there is a low, portion of the left opisthotic is present. The horizontal ridge formed by exoccipital and basioccipital is complete except for its slight opisthotic with a shallow depression dorsal to contribution to the base of the condylus it that also occurs, but to a variable extent in the occipitalis. The supraoccipital preserves its other Chedighaii and Bothremys specimens. The ventral body but lacks the posterior and ridge is more extensive in the type skull of dorsalmost portions of the crista supraoccipi- Chedighaii hutchisoni, but due to its thin, fragile 6 AMERICAN MUSEUM NOVITATES NO. 3655
A
Fig. 2. Bothremydina indeterminate. NCSM 18650, right otic chamber and occipital portion of skull. Campanian Tar Heel Formation, Bladen County, North Carolina. A, dorsal; B, ventral: C, posterior; D, anterior. [C. Facella, del.]. nature, it is liable to breakage and is not NCSM 14227, subtribe Bothremydina, ge¬ complete in other relevant specimens. In nus and species indeterminate; right otic NCSM 14227 (fig. 6) the ridge and depression chamber (fig. 6), Phoebus Landing, Bladen agree with those features in the type skull of County Landfill Annex, Bladen County, Chedighaii hutchisoni, suggesting that this dif¬ North Carolina, Tar Heel Formation, Late ference is probably due to individual variation. Cretaceous, Campanian. 2009 GAFFNEY ET AL.: NEW MATERIAL (PLEURODIRA: BOTHREMYDIDAE) 7
A
am
Fig. 3. Bothremydma indeterminate. NCSM 18650, right otic chamber and occipital portion of skull. Campanian Tar Heel Formation, Bladen County, North Carolina. A, dorsal; B, ventral: C, posterior; D, anterior. [C. Facella, del.].
NCSM 14227 preserves the right prootic, shows the sulcus eustachii and antrum post- most of the opisthotic, and much of the oticum. The surface of the area articularis quadrate. The cavum tympani is slightly more mandibularis is damaged. The basioccipital complete in this specimen than the others, and and basisphenoid are broken roughly on the AMERICAN MUSEUM NOVITATES NO. 3655
Fig. 4. Bothremydina indeterminate. NCSM 12766, right otic chamber. Campanian Tar Heel Formation, Bladen County, North Carolina. A, dorsal; B, ventral; C, right lateral; D, anterior. [C. Facella, del.]. midline. The posterior process of the ptery¬ This right otic chamber is broken just lateral goid is present as well as most of the right to the condylus occipitalis but seems to exoccipital, although it is damaged. The preserve the midline in the broken edge of opisthotic is also present but damaged on its the basisphenoid. It preserves the right half of occipital surface. the basioccipital, basisphenoid, and supraoc- This specimen has a larger overhang on the cipital (lacking the crista supraoccipitalis). anterior surface of the prootic and quadrate, The posterior process of the pterygoid with dorsal to the foramen stapediotemporale, than is the associated foramen posterius canalis car- seen in the other North Carolina specimens, otici interni lying between it and the quadrate although some ridge here is present in most is present. The quadrate lacks its lateral Bothremydini. The two measurements taken for contacts and much of the cavum tympani size comparison on these specimens show that but preserves the incisura columellae auris and NCSM 14227 is noticeably larger than the others. the ventral portion of the antrum postoticum. NCSM 12766, subtribe Bothremydina, ge¬ The antrum is preserved by being broken nus and species indeterminate; right otic along its length exposing it in dorsal view, as chamber (figs. 4,5,8; Gaffney et al., 2006: fig. figured in Gaffney et al. (2006: fig. 286D). The 286D), Phoebus Landing on Cape Fear River, canal holding the stapes is also clear in this Bladen County, North Carolina, Tar Heel specimen. The anterior surface of the otic Formation, Late Cretaceous, Campanian. chamber is eroded medially in the area of the 2009 GAFFNEY ET AL.: NEW MATERIAL (PLEURODIRA: BOTHREMYDIDAE) 9
Fig. 5. Bothremydina indeterminate. NCSM 12766, right otic chamber. Campanian Tar Heel Formation, Bladen County, North Carolina. A, dorsal; B, ventral; C, right lateral; D, anterior. [C. Facella, del.]. foramen stapedio-temporale and foramen Bladen County, North Carolina, Tar Heel nervi trigemini, exposing some of the interior Formation, Late Cretaceous, Campanian. morphology as well as the canalis cavernosus. NCSM 14103 preserves the right quadrate, NCSM 14102, subtribe Bothremydina, genus prootic, opisthotic, posterior portion of the and species indeterminate; right otic chamber pterygoid and a small portion of the medial (fig. 7A), Bladen County Landfill Annex, areas of the basisphenoid and basioccipital. Bladen County, North Carolina, Tar Heel The supraoccipital has some of the base of the Formation, Late Cretaceous, Campanian. crista supraoccipitalis present and the midline NCSM 14102 preserves the right quadrate, is determined from this. The area articularis prootic, opisthotic, posterior portion of the mandibularis is broken away. pterygoid and the medial areas of the basi- NCSM 14226, subtribe Bothremydina, ge¬ sphenoid and basioccipital. This specimen is nus and species indeterminate; left otic cham¬ less complete than the previous three but ber (fig. 1C), Bladen County Landfill Annex, shows more of the cavum labyrinthicum and Bladen County, North Carolina, Tar Heel agrees closely with them. Formation, Late Cretaceous, Campanian. NCSM 14103, subtribe Bothremydina, ge¬ This specimen preserves only the medial- nus and species indeterminate; left otic cham¬ most portions of quadrate, and small parts of ber (fig. 7B), Bladen County Landfill Annex, basiccipital, basisphenoid, pterygoid, supraoc- 10 AMERICAN MUSEUM NOVITATES NO. 3655
2 cm
am
Fig. 6. Bothremydina indeterminate. NCSM 14227, right otic chamber. Campanian Tar Heel Formation, Bladen County, North Carolina. A, ventral; B, anterior. [C. Facella, del.]. cipital, and exoccipital. The opisthotic and Bladen County, North Carolina, Tar Heel prootic are incomplete but better preserved. Formation, Late Cretaceous, Campanian. Nonetheless, the fragment shows useful areas This specimen consists of the processus of the otic chamber containing the foramen articularis and some of the cavum tympani posterius canalis carotici interni, foramen of the quadrate. stapediotemporale, and canalis cavernosus. NCSM 14228, subtribe Bothremydina, ge¬ The hiatus acusticus and its associated struc¬ nus and species indeterminate; right and left tures are also preserved. parietals, Bladen County Landfill Annex, NCSM 14577, subtribe Bothremydina, ge¬ Bladen County, North Carolina, Tar Heel nus and species indeterminate; left quadrate Formation, Late Cretaceous, Campanian. fragment, Bladen County Landfill Annex, These two parietals are consistent with the Bladen County, North Carolina, Tar Heel central portions of the parietals in Chedighaii Formation, Late Cretaceous, Campanian. hutchisoni but are too incomplete for further This specimen consists only of the processus comparison. articularis of the quadrate. NCSM 14499, Bothremys sp.; left ramus of NCSM 19721, subtribe Bothremydina, ge¬ lower jaw (fig. 9), Bladen County Landfill nus and species indeterminate; left quadrate Annex, Bladen County, North Carolina, Tar fragment, Bladen County Landfill Annex, Heel Formation, Late Cretaceous, Campanian. 2009 GAFFNEY ET AL.: NEW MATERIAL (PLEURODIRA: BOTHREMYDIDAE) 11
A
fpcci
Fig. 7. Bothremydina indeterminate. Ventral views of otic chambers. Campanian Tar Heel Formation, Bladen County, North Carolina. A, NCSM 14102, right otic chamber; B, NCSM 14103, left otic chamber; C, NCSM 14226, left otic chamber. All to same scale. [C. Facella, del.].
This partial lower jaw is of interest because it is dentary. The ramus is broken posteriorly at identified as Bothremys rather than Chedighai. about the level of the anterior margin of a pit NCSM 14499 preserves the dentary portion of of the sort seen in Bothremys. The dorsal the left ramus. The anteromedial margin of the surface of NCSM 14499 shows a thick lingual fragment is very close to the midline, allowing ridge rising posteriorly and a virtually flat a restoration of the jaw by flipping left to right labial ridge for most of its margin. Postero- (fig. 9). A small fragment of angular remains laterally, however, the labial ridge rises and in the anteriormost part of the contact thickens medially so that the anterior part of beneath the sulcus meckelii. The area of the the cone-shaped pit is formed between the coronoid bone is either broken or represented two ridges (fig. 9, compare with fig. 239B in by remains of the sutural surface on the Gaffney et al., 2006). 12 AMERICAN MUSEUM NOVITATES NO. 3655
Fig. 8. Size comparison of dorsal views of the more complete specimens of skulls of North American Bothremydidae of the sub tribe Bothremydina. Dashed line shows midline. All skulls to same scale. A, Chedighaii hutchisoni KUVP 14765 holotype (from Gaffney et al., 2006). B, Bothremys sp., FMNH PR 247 (from Gaffney et al., 2006). C, Bothremys cooki Leidy, 1865, AMNH 2521 holotype skull and AMNH 29444 right otic chamber (from Gaffney et al., 2006). D, Chedighaii sp. ALAB PV 2001.2 (from Gaffney et al., 2006). E, Bothremydina indeterminate, NCSM 12766. F, Bothremydina indeterminate, NCSM 18650. [F. Ippolito, C. Facella, J. Dowis, del.]. 2009 GAFFNEY ET AL.: NEW MATERIAL (PLEURODIRA: BOTHREMYDIDAE) 13
Fig. 9. Bothremys sp. NCSM 14499, left ramus of lower jaw. Right side reversed in a partial restoration. [C. Facella, del.].
NCSM 14499 is almost indistinguishable has what appears to be the ventral surface of a from the lower jaw of FMNH PR 247, here well-developed pit of the sort seen in FMNH identified as Bothremys sp. NCSM 14499 does PR 247, a Bothremys lower jaw, in contrast to differ from FMNH PR 247 in having a slightly the shallower concavity seen in ALAB PV straighter lingual ridge and a slightly larger 2001.2, a Chedighaii lower jaw. size. It is also likely that NCSM 14499 had a NCSM 23681, Chedighaii sp.; partial right wider symphyseal concavity, if our reconstruc¬ maxilla and jugal (fig. 10), Bladen County tion is correct. The lower jaws of Bothremys Landfill Annex, Bladen County, North and Chedighai are described and figured in Carolina, Tar Heel Formation, Late Gaffney et al., (2006), and the distinction Cretaceous, Campanian. between the genera can be seen by comparing The single fragment, NCSM 23681, consists fig 242B with fig. 242E (both correctly of a partial right maxilla, the adjacent part of identified in the caption for figure 242 in the jugal, and a small portion of the premax¬ Gaffney et al., 2006, as Bothremys sp. and illa. The central part of the maxilla and the Chedighai sp. respectively, as this caption was lateralmost part of the jugal where it attaches corrected in proof). Presciently, Gaffney et al. to the maxilla are the areas present. The frag¬ (2006: 527) stated: “If FMNH PR 247 proves ment is mostly bordered by broken edges but to be a jaw type that is found with a pitted the lower orbital margin is a natural edge. skull in the future, uh oh, a change is in the Although incomplete, the bone is well preserved wind.” And sure enough this is what has and undistorted. As far as can be determined, happened. Therefore, NCSM 14499 can at NCSM is very similar in morphology to ALAB present be identified as Bothremys because it PV 2001.2, figured and described in Gaffney et 14 AMERICAN MUSEUM NOVITATES NO. 3655
Fig. 10. Chedighaii sp. NCSM 23681. Right maxilla and jugal fragment. Jugal bone indicated by grey tone. A, B, lateral view; C, D, posterior view; E, F, ventromedial view; G, H, ventral view. [F. Ippolito, del.]. 2009 GAFFNEY ET AL.: NEW MATERIAL (PLEURODIRA: BOTHREMYDIDAE) 15 al. (2006: figs. 160, 161, 164, 165). It should be genus significantly affects the shape of both noted that a partial right maxilla of ALAB PV jugal and maxilla in exactly the area preserved 2001.2, less complete than the figured left in NCSM 23681, so the absence of a pit and maxilla, was not figured in Gaffney et al., but the presence of a relatively flat triturating is used in the present comparisons with NCSM surface can be determined even in this small 23681. ALAB PV 2001.2 was identified as fragment. The foramen praepalatinum is Chedighaii barberi in Gaffney et al. (2006), but visible in this view, although most of the area this is updated here to Chedighaii sp. Both surrounding it is damaged. A small portion of NCSM 23681 and ALAB PV 2001.2 appear to the fossa nasalis is visible anteriorly. be from animals of approximately the same size. The posterior view (fig. 10C, D) of NCSM In lateral view (fig. 10A, B) NCSM 23681 23681 shows the septum orbitotemporale, the shows the lateral surface of the maxilla anterior wall of the fossa temporalis. Most of anterior to the jugal exposure, which is not this side of the wall is formed by jugal, as in preserved in the lateral view of this fragment. the other bothremydids. The ventral margin is a broken edge that is In summary, NCSM 23681 is identified as dorsal to the ventral edge of the labial ridge, Chedighaii, in contrast to Bothremys, because it which is represented only by a broken surface. has no pit on the triturating surface, a relatively The lateral surface of ALAB PV 2001.2 is flat triturating surface, and a large ridge distinctly curved, convex laterally, while in forming the ventral margin of the orbital rim. NCSM 23681 this surface is flat, possibly accentuated by the absence of the ventral NEW CRANIAL MATERIAL OF margin in NCSM 23681. The dorsal edge of Bothremys sp., FMNH PR 247, FROM THE NCSM 23681 shows the ventral margin of the MOOREVILLE CHALK OF ALABAMA orbital rim, a deep ridge in Chedghaii in contrast to the rounded ventral margin, FMNH PR 247 consists of a partial skull lacking a ridge, characteristic of Bothremys (Gaffney et al., 2006: figs. 162, 163; Gaffney (Gaffney et al. 2006). and Zangerl, 1968: figs. 17, 18, 19D), lower In the ventromedial view (fig. 10E, F) of jaws (Gaffney et al., 2006: figs. 242, 244; NCSM 23681 the fossa orbitalis lies above the Gaffney and Zangerl, 1968: fig. 22D, E), and flat plate of the maxilla and jugal that together an associated shell (Gaffney and Zangerl, form the triturating surface of the palate. The 1968: figs. 2, 3). It is from the Campanian septum orbitotemporale lies at the posterior- Mooreville Chalk (Selma Formation of most edge of NCSM 23681 defining the Zangerl, 1948), one mile east of Harrell, anterior wall of the fossa temporalis. The Dallas Co., Alabama. This specimen is im¬ foramen praepalatinum is visible anteriorly, portant in showing the association of the skull broken along its length so most of the canal is and jaws with pits with the type of shell exposed. The position of this foramen/canal is described as Podocnemis barberi by Schmidt shown in the endocast YPM PU 12951, (1940). It was identified in Gaffney et al. Chedighaii sp., figured in Gaffney et al. (2006: (2006: figs. 162, 163, and text) as Chedighaii figs. 166, 167) but not in ALAB PV 2001.2, as barberi, but a newly identified skull fragment the area is not preserved in that specimen. The of FMNH PR 247 (figs. 11-14) shows that foramen praepalatinum is usually formed by this identification was in error. FMNH PR the premaxilla but the premaxilla-maxilla 247 belongs to Bothremys and not to suture is not clear in NCSM 23681. Chedighaii based on diagnostic cranial criteria. In ventral view (fig. 10G, H) NCSM 23681 A portion of the right maxilla and jugal is the preserved area of the triturating surface is present among the fragments of FMNH PR relatively small, consisting only of the central 247. As with the rest of the material in this section lacking the labial ridge and lingual specimen, its edges are partially eroded. The ridge. The preserved section is nearly horizon¬ maxilla consists of the deep labial ridge as a tal, and slightly concave, agreeing closely with natural edge laterally. Posteriorly, the lateral ALAB PV 2001.2. There is no pit structure as edge of the septum orbitotemporale is also seen in Bothremys. The pit formation in that preserved. The ventral surface forms the 16 AMERICAN MUSEUM NOVITATES NO. 3655
Fig. 11. Bothremys sp. FMNH PR 247. Right maxilla and jugal fragment. A, dorsolateral (at right angle to plane of fragment); B, ventromedial (opposing side of orientation in A); C, ventral (oriented as it would appear in skull, as in fig. 12); D, posteromedial. [F. Ippolito, del.]. lateral and anterolateral part of the triturating cooki. The pit in FMNH PR 247, however, surface including the lateral part of the seems to have a thinner posterior wall so that triturating pit. The medial and posteromedial the pit is closer to the fossa temporalis. Another edges have a narrow portion of the jugal difference between the two specimens is the attached, and the jugal suture is visible along position of the maxilla-jugal suture. In B. cooki the septum orbitotemporale and along the the jugal forms the entire dorsal portion of the triturating pit. pit, but in FMNH PR 247 the jugal forms a The labial ridge of FMNH PR 247 is smaller portion of the piece preserved. blunter and thicker than the labial ridge in Nonetheless, in common with B. cooki and in Bothremys cooki, but the shape of the slope contrast to the other species of Bothremys, the into the triturating pit is similar in both. jugal is widely exposed along the ventral margin Comparison of the preserved portion of the of the septum orbitotemporale, and there is no pit in FMNH PR 247 and B. cooki also shows maxilla-pterygoid contact. a close similarity. Although not preserved, the The newly identified skull fragment from known portions of the septum orbitotemporale FMNH PR 247 consists of a part of the in FMNH PR 247 support restoring the pit in articulated left jugal and left maxilla that form FMNH PR 247 as completely enclosed as in B. the lateral wall of the triturating surface and cooki. It is likely that the pit in FMNH PR 247 cheek. This fragment, although small and not has the same relative size and depth as in B. well preserved, shows the lateral part of the pit 2009 GAFFNEY ET AL.: NEW MATERIAL (PLEURODIRA: BOTHREMYDIDAE) 17
Fig. 12. Bothremys sp. FMNH PR 247. Right maxilla and jugal fragment. Labeled drawings for figure 11. [F. Ippolito, del.]. structure on the triturating surface as seen in However, in Gaffney et al. (2006) the senior Bothremys (fig. 12). It should be kept in mind author placed the species barberi in Chedighaii that three of the four known species of on the basis of the close similarity of the shell Bothremys consist of skulls without associated of FMNH PR 247 with the type shell of shells (B. arabicus has a skull associated with a Podocnemis barberi Schmidt, 1940, FMNH partial plastron; Zalmout et al., 2005) and that P26055. This identification was done with the type specimen of the type species of the some qualification (see Gaffney et al., 2006: genus Chedighaii, Chedighaii hutchisoni Gaffney 86-90 for further discussion) due to the et al., 2006, is also a skull. Therefore, the only apparent absence of confirming skull material. distinguishing features of these genera, based on The recognition of triturating pits in the jugal- the types, are within the skull. All species of maxilla skull fragment in FMNH PR 247 Bothremys have well-developed triturating pits, makes this identification incorrect. Although which are absent in Chedighaii. The skulls also FMNH PR 247 has triturating pits and is differ in shape as well as in the presence/absence correctly assigned to Bothremys, the assign¬ of triturating pits. ment of it to a species is now unclear. 18 AMERICAN MUSEUM NOVITATES NO. 3655
Fig. 13. Bothremys sp. FMNH PR 247. Ventral view of skull with maxilla-jugal fragment placed in its likely position. [F. Ippolito, del.].
Basically, the shell morphology in North unlikely to be B. cooki (fig. 8). The maxilla American Bothremydina is inadequate to fragment of FMNH PR 247 is thicker and, provide species identifications at present. moreover, less acute along its labial ridge than This is not surprising as Gaffney et al. (2006) in B. cooki. When originally described by concluded that the shell of Pelomedusoides is Gaffney and Zangerl (1968), FMNH PR 247 very conservative compared with the skull. was readily assigned to the genus Bothremys The possible polymorphism of the pitted because of the pits in the lower jaws, and the triturating morphology, either related to species identification was based on the shell gender, diet, growth, or some other factor, is morphology. At the present time, however, discussed at length in Gaffney et al. (2006: 76- shells very similar to the type shell of barberi 79). Although it cannot be ruled out with apparently occur in at least two genera certainty, we agree with those authors that it is associated with both pitted (FMNH PR 247) unlikely that the pits differentiating the pitless and nonpitted (ALAB PV 2001.2) skull types. Chedighaii from the pitted Bothremys are best Therefore, at present, we identify FMNH PR interpreted as variation within one polymor¬ 247 as Bothremys sp., even though it is likely phic species. There are more characters than to be a distinct species from the only other the pits differentiating other skulls of these North American Bothremys species. species, although they are all in the anterior The skull/shell association identified in part of the skull and possibly related. Gaffney et al. (2006) as Chedighaii barberi, Whether FMNH PR 247 should be identi¬ ALAB PV 2001.2, can still be identified as fied as Bothremys barberi, Bothremys cooki, or Chedighaii on the basis of its skull (Gaffney et one of the other Bothremys species is a al., 2006: figs. 160, 161, 164, 165), which difficult question because the skull of clearly lacks pits and is similar to Chedighaii FMNH PR 247 is incomplete. However, on hutchisoni. Its shell is also very similar to the the basis of size alone, FMNH PR 247 is type shell of “Podocnemis” barberi, (see 2009 GAFFNEY ET AL.: NEW MATERIAL (PLEURODIRA: BOTHREMYDIDAE) 19
Fig. 14. Bothremys sp. FMNH PR 247. Ventral view of skull with maxilla-jugal fragment placed in its likely position and reversed, placed on outline based on other Bothremys skulls (from Gaffney et al., 2006). [F. Ippolito, del.]. below). However, ALAB PV 2001.2 is prob¬ barberi. Because this specimen has an associ¬ ably a different species of Chedighaii from ated partial skull and shell, it was the basis for Chedighaii hutchisoni. The maxilla of the placing the species “Podocnemis” barberi former is narrower and the orbits more Schmidt 1940, the type of which is a shell laterally facing than in the latter. YPM PU only (Schmidt, 1940; Gaffney et al., 2006: fig. 12951 and NCSM 23681 probably belong to 264), in Chedighaii. But a newly identified this species as well. Nonetheless, the material skull fragment of FMNH PR 247 shows that is insufficient to base a new species, so this identification was in error. FMNH PR Chedighaii sp. is the best identification at 247 belongs to Bothremys and not to present. Chedighaii based on the diagnostic cranial In summary, FMNH PR 247, an associated criteria. However, even though this specimen partial skull and shell from the late Cretaceous is not a type, a taxonomic consequence of this of Alabama, was described and figured in new identification is the ambiguous generic Gaffney and Zangerl (1968) as Bothremys assignment of the shell-based species barberi: barberi, and identified in Gaffney et al. it is not possible to determine whether barberi (2006: figs. 162, 163 and text) as Chedighaii belongs to Bothremys or Chedighaii. The 20 AMERICAN MUSEUM NOVITATES NO. 3655
Fig. 15. Chedighaii sp. ALAB PV 2001.2. Plastron with associated skull. A, dorsal; B, ventral. [F. Ippolito, del.].
species barberi is not the type species of any THE SHELL OF Chedighaii sp., ALAB PV genus so its assignment does not affect the 2001.2, FROM THE MOOREVILLE taxonomic basis of these genera, it affects only CHALK OF ALABAMA the identification of shell-only specimens. The other specimens identified in Gaffney et ALAB PV 2001.2 (field no. 00-5-9) consists al. (2006) as Chedighaii barberi that consist of of a partial skull (Gaffney et al., 2006: figs. shells, or parts of shells, can be identified only 164, 165), lower jaws (Gaffney et al., 2006: as subtribe Bothremydina indeterminate. The figs. 242-244), and a nearly complete plastron natural endocast identified as Chedighaii (figs. 15,16) and anterior section of carapace barberi, YPM PU 12951 (Gaffney et al., (fig. 17), from the Gaston’s pond, 1.5 mi. 2006: figs. 166, 167), can still be identified as SSW of Harrell, Dallas Co., Alabama, Chedighaii sp. It clearly lacks triturating pits Campanian Mooreville Chalk. The specimen and is most similar to ALAB PV 2001.2. was collected from the bottom of a dry catfish 2009 GAFFNEY ET AL.: NEW MATERIAL (PLEURODIRA: BOTHREMYDIDAE) 21
A B
Fig. 16. Chedighaii sp. ALAB PV 2001.2. Plastron. Solid lines are sutures, dotted lines are scales. A, dorsal; B, ventral. See Gaffney et al. (2006: fig. 264) for labeled drawings of the similar Bothremys/Chedighaii barberi shell. [F. Ippolito, del.]. pond by ALAB volunteers under supervision lateral edges and ventral portions. The sulci of Ed Hooks. Prior to its discovery, it had are largely missing, but the sulcus between been trampled upon for an indeterminate vertebrals one and two and the sulcus between number of years by cattle from the adjoining right pleurals one and two are visible. pasture coming to drink. This, along with The preserved elements agree closely with subsequent erosion following the receding those figured as “Bothremys or Chedighaii water level in the pond, resulted in in situ barberi” in Gaffney et al. (2006: fig. 264). The finds of only larger fragments of the plastron. bones are thicker and the specimen is larger The remainder of the specimen, comprising than most of the Selma Formation specimens of several hundred fragments, was scattered over “Podocnemis alabamae” Zangerl (1948). On the approximately 100 m2 and was recovered by external surface the texture is very smooth (the surface collecting and dry/wet screening. “pavingstone turtle” of Schwimmer, 1986: 116, The carapace (fig. 17) is incomplete and is a presumed Bothremydina), but without the represented only by a portion of the anterior surface pitting and irregularities seen in YPM third consisting of the following elements: 3608, “Bothremys barberi, subspecies C” of right and left costals one; right costals two, Gaffney and Zangerl (1968). One of the few three, most of four, and a small part of five; sulci visible, the transverse sulcus separating neurals one, two, and parts of three and four; pleural scales one and two, lies in the middle of and right and left peripherals three lacking costal two in ALAB PV 2001.2, rather than 22 AMERICAN MUSEUM NOVITATES NO. 3655
Fig. 17. Chedighaii sp. ALAB PV 2001.2. Anterior section of carapace. A, dorsal; B, ventral; C, dorsal; D, ventral. See Gaffney et al. (2006: fig. 264) for labeled drawings of the similar Bothremys! Chedighaii barberi shell. [F. Ippolito, del.]. close to the anterior edge of costal two, as in The plastron (figs. 15,16) is nearly com¬ FMNH P26055, the type of “Podocnemis” plete, although the bridge areas are missing barberi Schmidt, 1940. The carapace features and only a fragment of the right mesoplastron used to compare “Chedighaii barberi” shells in remains. The sulci are clear and the sutures Gaffney et al. (2006: table 23) are all indeter¬ determinable except in a few areas. The minate except for the first neural length. plastron agrees with the described specimen, Although the nuchal in ALAB PV 2001.2 is FMNH P26055, used by Schmidt (1940) as the damaged, it can be interpreted as slightly longer type of his “Podocnemis barberi” except in a rather than much longer than neural two, few areas. In FMNH P26055 the anterior lobe agreeing with all but YPM 3608 among the is semicircular with no gular enlargements, but compared shells. in ALAB PV 2001.2 the epiplastra are swollen On the internal surface, the attachment scars in the area of the gular scales to form a for the axillary buttress in ALAB PV 2001.2 are transverse anterior margin of the plastral lobe. very close in shape, extent, and orientation to The median epiplastral suture is slightly longer the scars in ANSP 15902 and the Alabama in FMNH P26055 than in ALAB PV 2001.2. specimens identified by Zangerl (1940) as The epiplastron in ALAB PV 2001.2 is nearly “Podocnemis alabamae.” These specimens differ identical to that in ANSP 15902 in contrast to in axillary scar orientation from YPM 3608 FMNH P26055. Another area of variation is because in YPM 3608 the scar is angled slightly the anal notch formed by the xiphiplastra. more acutely to the midline. FMNH P26055 has a wider, more U-shaped The number of neurals, nuchal emargina- notch, while ALAB PV 2001.2 has a narrower, tion, and carapace shape are indeterminate. V-shaped notch. 2009 GAFFNEY ET AL.: NEW MATERIAL (PLEURODIRA: BOTHREMYDIDAE) 23
SYSTEMATIC VARIATION IN THE The Kansas specimen (YPM 3608) has a SHELL OF NORTH first neural that is relatively longer than in the AMERICAN BOTHREMYDINA other specimens but, along with its uniquely shallow nuchal emargination, does not help in Because the type of the species barberi forming groups among the shells. The axillary (Schmidt, 1940) consists only of a shell, the buttress in YPM 3608 also seems to be at a important question for Bothremydina system- more acute angle to the midline than seen in atics posed by the limitation of generic diag¬ the other Bothremydina specimens. nostic characters to skulls is whether the two The vertebral scales of “Podocnemis alaba- named North American Bothremydina genera mae” FMNH P27370 and FMNH P27372 are can be distinguished by shell morphology alone. wider relatively than in the other specimens. After study of this material, the answer seems to This character is indeterminate in the two be no (although there is one possible exception, shells with skulls. It does not coincide with any see below). In any case, this is not a surprising other character and may be growth related, as situation, as Gaffney et al. (2006) argue that the juveniles usually have wider vertebrals. shell morphology among Pelomedusoides does The plastron seems to provide more oppor¬ not vary much compared with the quite diverse tunity for systematic variation in Pelomedus¬ skull morphology. oides, and was the basis for Zangerl’s (1948) Although there are many individual frag¬ phylogeny. Among the available specimens of ments attributable to Bothremydina from Bothremydina from North America, the plas¬ North America, the number of reasonably tron has the only characters with a potential complete shells is unfortunately few. Table 4 for systematic significance. Although the lists nine shells that are well-enough preserved plastra are generally very similar, there are to make useful comparisons, although there are present in collections some undescribed some differences. The first and probably most material that might prove useful in the future. important is the shape of the anterior lobe. In PV 2001.2 (one of two shells with an associated The carapaces of the listed specimens differ in a few characteristics. Overall shape is wider skull, it is attributable to Chedighaii), YPM than long for all except FMNH P26055, the 3608, and FMNH P27369, the anterior margin type of Podocnemis barberi Schmidt, 1940, is straight, the epiplastra in the area of the gular which was reconstructed three-dimensionally, scales are swollen causing this change in outline. while the others are flattened. The nuchal In the other shells, FMNH P26055 (type of emargination is particularly shallow in the Podocnemis barberi Schmidt, 1940), FMNH PR Kansas shell, YPM 3608 (Gaffney and 247 (one of two shells with an associated skull, it Zangerl, 1968: figs. 9-12). It is significantly is attributable to Bothremys), FMNH P27370, deeper in the other shells except for FMNH and ANSP 15902, the anterior lobe has a P27369 in which it is about intermediate broadly semicircular outline and the epiplastra between YPM 3608 and the other shells. are not swollen. Although the two skull- The neural number is a discrete variation associated specimens provide considerable sup¬ noted by Zangerl (1948) in describing porting evidence from the skulls that coincide “Podocnemis alabamae.” The Arkansas type with this single plastral character, there are no of barberi (Schmidt, 1940) has six neurals and other postcranial characters that seem to have the Alabama type of alabamae (Zangerl, 1948) this distribution. The shallow nuchal emargi¬ also has six. Within the Mooreville Chalk nation of YPM 3608 and the somewhat shallow (Selma Formation of Zangerl, 1948) collection nuchal of FMNH P27369 agree with the there are two carapaces with seven neurals and straight anterior plastral lobe character, but four carapaces with six neurals. Neural the key specimen, ALAB PV 2001.2, a skull- variation is common in recent pelomedusids shell association, has no nuchal. and podocnemidids. Zangerl attributed this Nonetheless, a character is a character and variation to intraspecific variation of no this one plastral character could be used to systematic value. Among the available mate¬ support identification of the type of rial, neural number does not coincide with any Podocnemis barberi Schmidt, 1940, FMNH other character. P26055, as Chedighaii. One problem with this 24
TABLE 4 Comparison of North American subtribe Bothremydina shells Ph Ho 2 (NK-SQ hh soq,^sE: Z © i-i ctfclc pd Pd 60, 60 3 «1S- 3 'G PP a s >a a Ph CIS!PH c6 Pd o , Pd 60 ,__PH ;_| 43 Entoplastron nearly no no no yes no straight posteriorly NO. 3655 2009 GAFFNEY ET AL.: NEW MATERIAL (PLEURODIRA: BOTHREMYDIDAE) 25 interpretation is that the shells from the Selma The other plastral characters show erratic Formation, “Podocnemis alabamae” of Zangerl variation. The median contact of the epiplas- (1948), which come from the same area and tra is longer in YPM 3608 than in the other horizon and seem to be the same species on all specimens, although FMNH P26055 is inter¬ other criteria, contain both plastral types and, mediate. In ANSP 15902 the entoplastron is therefore, two species and genera distinguished equidimensional, while in all the other plastra on the basis of one character. But more it is wider than long. The anal notch (a importantly, this character varies rather widely longtime favorite of shell enthusiasts) can be within species of recent cryptodires and pleur- divided into ones that are more U-shaped and odires. Although it would be convenient and wider versus ones that are more V-shaped and would provide a neat solution to the barberi narrower. Unfortunately, the two skull-shell problem, in the opinion of the senior author, it associated specimens are both V-shaped along is unlikely to be supported by future work. with FMNH P27369, with the other shells Although this character has not yet been (FMNH P26055, FMNH P27370, ANSP adopted, future workers should keep it in mind 15902) more U-shaped. when working on material of this group. Until a more compelling set of character Another potentially important plastral distributions are identified in the shells, it character (brought to our attention by Ren seems best to leave the shell-only specimens in Hirayama) is the straighter posterior margin nameless limbo, generically speaking. of the entoplastron in ALAB PV 2001.2 in contrast to the more pointed margin in ACKNOWLEDGMENTS FMNH PR 247 and other shells. As ALAB PV 2001.2 is associated with a skull identifi¬ We would like to refer the reader to the able as Chedighaii, and FMNH PR 247 has a Acknowledgements section of Gaffney et al. skull identifiable as Bothremys, this may be an (2006) for a complete list of people that aided important differentiating character. The type our research on pleurodires. Collectors of the of “Podocnemis” barberi, FMNH P26055, and North Carolina material (in addition to the shell-only specimens, YPM 3608 and V.P.S.) are Frank and Becky Hyne, Terry ANSP 15902, also have what could be Denny, Don Clements, Kevin Shannon, and considered straighter contacts, although none Mark Hurst. We are grateful to the Gaston are nearly as shallow as ALAB PV 2001.2. family (owner) and Charles Dunkin (leaser) Close examination of ALAB PV 2001.2 shows for permission to collect at Gaston’s pond, that the straighter contact is partly due to Alabama. Thanks to the hard-working ALAB breakage and the presence of plaster filling the volunteers for the discovery and initial prep¬ entoplastron-hyoplastra contact. Also, the aration of ALAB PV 2001.2. We appreciate internal (dorsal) length of the entoplastron is the later preparation at AMNH by Ed greater than the external (ventral) length, with Pedersen. We appreciate the efforts of our the degree of entoplastron ventral lengthening illustrators: Frank Ippolito, Senior Scientific Assistant, AMNH, and Christine Facella, a the result of the overlap of a thin ridge of participant in the AMNH Visiting Artist hyoplastron. Consequently, all the specimens Program. We thank our two reviewers, Ren show some variation, and FMNH P26055, Hirayama and an anonymous reviewer for YPM 3608, and ANSP 15902 could be their help in improving the paper. considered intermediates. This character does This paper was submitted on January 14, not have the same distribution as any of the 2008, and accepted for publication on July 3, others and is inconsistent with the plastron 2008. width character. The presence of the more pointed entoplastron in the type of “Podocnemis” barberi, FMNH P26055, sup¬ REFERENCES ports putting it in Bothremys, in contrast to Baur, G. 1891. 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Late Cretaceous fossils Michigan 31(6): 155-177. from the Blufftown Formation (Campanian) in Zangerl, R. 1948. The vertebrate fauna of the Selma western Georgia. The Mosasaur 3: 109-124. Formation of Alabama. I. Introduction. II. The Self-Trail, J.M., R.A. Christopher, D.C. Prowell, pleurodiran turtles. Fieldiana Geology and R.E. Weems. 2004. The age of dinosaur¬ Memoirs 3(1 and 2): 1-56. Complete lists of all issues of the Novitates and the Bulletin are available at World Wide Web site http://library.amnh.org/pubs. Inquire about ordering printed copies via e-mail from [email protected] or via standard mail from: American Museum of Natural History, Library—Scientific Publications, Central Park West at 79th St., New York, NY 10024. TEL: (212) 769-5545. FAX: (212) 769-5009. @ This paper meets the requirements of ANSI/NISO Z39.48-1992 (Permanence of Paper).